1. Field of the Invention
The present invention relates to a joint structure for a robot.
2. Description of the Related Art
In a joint structure in which a robot arm and a wrist are connected to each other, techniques for increasing a pressure in the interior of the robot arm and the wrist to improve a drip-proof property have been known (e.g. Japanese Unexamined Patent Publication (Kokai) No. H7-75992).
In the joint structure as described above, a technique for preventing outflow of a lubricant which is charged to the interior of the joint structure while improving a drip-proof property has been demanded.